The invention relates to apparatus for dispensing volatile liquids, such as fragrances and air freshening substances. It is particularly concerned with such dispensing apparatus for use in vehicles, especially road vehicles.
One problem encountered with the use of liquid fragrances and fresheners in road vehicles is that there are frequent periods, often lengthy, when the vehicle is not in use but the liquid continues to volatilise. If the vehicle interior is completely closed, as is often the case when the vehicle is not in use, high concentrations of the volatilised material can accumulate in the atmosphere in the vehicle, especially as the closure of the interior frequently results in a considerable temperature increase. The result can be unpleasant for the occupants when the vehicle is next used, and is wasteful of the material being dispensed.
It is an object of the invention to at least ameliorate these problems.
According to one aspect of the invention, there is provided a dispensing apparatus for a volatile liquid comprising a container having a substantially closed interior space for the liquid and at least one capillary passage for communication with the exterior extending from an upper region of the interior space adjacent an upwardly extending wall or partition of the container, whereby liquid displaced onto said wall or partition to reach said at least one capillary passage can be drawn therethrough to be released from the container.
With such an apparatus located in a moving vehicle, the inertia of the liquid causes it to be displaced in the container as the vehicle changes speed or direction. By arranging that the liquid then reaches said at least one capillary passage it can be dispensed from the container while the vehicle is moving.
Preferably, the container is mounted on a support in an upright position but is tiltable thereon by a transverse inertia force in the same direction as the direction of displacement of the liquid. The container can thus be itself displaceable by inertia forces generated during the motion of the vehicle, so that its tilting will assist the displacement of the liquid towards said at least one capillary passage.
According to another aspect of the invention, a dispensing apparatus is provided for a volatile liquid, comprising a container with substantially closed interior space having at least one capillary passage opening into an upper peripheral region of the interior space for communication with the exterior, and a mounting on which the container is tiltably supported, return means acting between the mounting and the container urging the container to an upright position on the mounting, the container being able to tilt against the action of said return means under the influence of inertia forces acting transversely upon it.
Preferably, the container is in the form of a bowl with a side wall sloping upwards and outwards from a central bottom region towards said at least one capillary passage. The angle of slope to the horizontal will normally be at least 15xc2x0, but can be considerably greater. In particular, if the container is arranged to be tiltable, an angle of slope of between 30xc2x0 and 60xc2x0 is preferred. At least the upper region of the side wall can conveniently have a substantially conical shape.
In a dispenser according to the invention, it is convenient to arrange said at least one capillary passage to open into the interior of the container adjacent around substantially the entire periphery of the container upper region so that said passage or passages can collect liquid displaced in any direction from the lower region in which it is normally at rest.
In a particularly convenient arrangement, the container is rotationally symmetrical and a pair of abutting or closely adjacent plates extending close to the periphery of the container upper region form said capillary passage or passages at their interface, so that liquid reaching the interface at any point around the periphery is drawn through the passage or passages inwards by the capillary action to a central upper region of the container from where it can escape to the exterior. Preferably, at the outlet end of the passage or passages there are distribution means to assist the volatilisation and dispersion of the liquid.
Any ability of the container to tilt in response to disturbing forces generated by the movement of the vehicle is preferably limited, to limit the exposure of the liquid to said capillary passage or passages. This maximum angle of tilt may be related to any initial slope of the wall or partition along which the liquid travels;
desirably, the tilt is limited to give the container wall a final slope at a minimum angle of not substantially less than 15xc2x0 to the horizontal, and preferably not substantially less than 25xc2x0. The liquid will of course also be tilted and it may be arranged that under normal manoeuvring conditions the liquid surface tilt will approximately correspond to the final angle of slope of the container wall adjacent the capillary passage.
The depth of liquid at rest in the container is another factor, and in a further preferred feature, means are provided to limit the filling level of the container to some distance below said at least one capillary passage, so that the displaced liquid does not reach the passage too easily due to overfilling.